US2809544A - Plastic wall tile for packing - Google Patents

Description

oct. 15, 1957 M MACCAFERR; 2,809,544

PLASTIC WALL TILE FOR PACKING O INVbNTOR',

Y (BALL/121A@ ATTORNEYb Oct. 15, 1957 M. MACCAFERRI 2,809,544

PLASTIC WALL TILE FOR PACKING Filed Sept. 22, 1954 2 Sheets-Sheet 2 ATTORNEY.,

ignited States Patent 'i Prasrrc WALL ma non PACKING Mario Maccaferri, Rye, N. Y.

Application September 22, 1954, Serial No. 457,593

3 Claims. (Cl. 72-18) This invention relates to certain improvements in plastic wall tile and in the design and construction thereof by which such tiles will be maintained in proper positions relative to each other when stacked for packing and when in the packaged forms made up of the'tile stacks; and the nature and objects of the invention will be readily recognized and understood by those skilled in the art to which the invention relates from the following detailed description and explanation of the accompanying drawings illustrating several embodiments or structural expressions of the invention from among various other forms, embodiments and constructions of which the invention is capable within the broad spirit and scope thereof as defined by the claims hereto appended.

Plastic wall tiles are now being manufactured and eX- tensively sold in very large quantities and are in widespread general use. Such tile are usually molded from plastic material and take the form of a veiy thin, lightweight tile body having at the rear side thereof a relatively thin rearwardly extending edge flange therearound by which the tile is installed on a surface to be covered thereby. The front sides of the tiles are usually generally planar and provide the decorative faces thereof which are exposed with the tiles in installed positions. These thin, lightweight tiles are usually installed in position by setting the rear flanged sides thereof into a suitable mastic or cement coating which has been applied over the surfaces to be covered by the tile. The front decorative surfaces of these plastic tiles have characteristics such that they are very readily scored or marred by Contact with any even lightly abrasive surface, in fact, they are easily scored or marred by rubbing or sliding engagement with the similar decorative surface of another of such tiles, such as caused by vibration between packaged tiles in transit, particularly if such surfaces are canted or tilted out of parallelism with each other.

The manufacturers of these plastic wall tiles generally follow the practice of packing the tiles by piling them in stacks made up of pairs of tile with the tiles of each pair placed back-to-back, that is, with the flanged rear sides thereof in abutting engagement. When the tiles are so packed, the generally planar front faces of each pair tiles in a stack are at opposite sides of the pair and abut and are in engagement against the faces of the adjacent tiles of adjacent pairs. The tiles are usually package-'l storage and shipment by placing a plurality of such of pairs of tiles so arranged in a box or carton v, i l may then be suitably closed or wrapped to contain and hold the tiles until the package opened for use. The tiles when so packaged are not tightly bound but are relatively loose in t. e carton or package, so that vibration, such as particularly encountered during transportation of the packaged tiles causes the engaged surfaces of the tiles to rub against each other.

This generally practiced method of packing and packaging these plastic Wall tiles has developed a serious problem in high cost of packaging and in the number of tile damaged through front face marring occasioned by Patented Oct. 15, 1957 r'ice rubbing engagement between adjacent front faces of the tiles in the stacks thereof in the package. It is found when so packing the tiles in stacks that due to the engaged flanged rear sides of the pairs of tiles, one tile of a pair will tend to, and frequently does, shift from the de-A sired position of substantial parallelism with the other tile of the pair and with the tile adjacent thereto in a stack and because of the edge angcs will then, in effect, be constrained into that position against normal relative movement back to a position of parallelism. When so canted or tilted out of parallelism with the adjacent tiles, the engaged front faces of adjacent tiles will then very readily score or abrade and be marred or defaced to an extent such that the tile is not acceptable to the purchaser or user for installation. This results in substantial numbers of the tiles being rejected or returned to the manufacturer or seller thereof. With pairs of back-to-back tiles in a stack maintained in parallelism it will be found that there is greater resistance to relative movement offered between the engaged faces of adjacent pairs than between the engaged backs of a pair due to the greater area of surface engaged between the tile faces than engaged between the tile backs. ln addition there tends to be a static locking between the engaged faces which increases the resistance to relative movements therebetween. Thus, l have discovered that if the tiles can be maintained substantially parallel, then the relative movements therebetween such as caused in transit, can be substantially limited to movements between the backs of each pair of tiles with surface marring movements by engaged tile faces substantially eliminated.

The plastic wall tile manufacturing industry has, in an attempt to overcome or reduce this problem, resorted to the practice of placing an individual piece of paper, tissue or the like thin material between the faces of adjacent tiles in a stack of tiles for packaging in order to try to prevent the marring, scoring or other defacernent of the tile surfaces due to tilting or canting of the tiles in relative movements therebetween. The insertion of such protective papers or tissues between faces of adjacent tiles has not, however, provided a satisfactory solution to the problem, primarily because of the very substantial expense in labor and materials, particularly as it was found that the cheaper grades of paper or tissues presented abrasive characteristics that merely forrned a new source of marring or defacing of the tile faces when the tiles shifted or canted and tilted relative to each other in the packaged tiles under the conditions encountered from vibration in transit and in the handling of the tile packages. While grades or characters of papers and tissues have been found that were more suitable for the protective purposes for which intended than the cheaper grades, nevertheless the very high cost thereof makes their use almost prohibitive in the highly competitive plastic wall tile market. And in addition to the foregoing diiliculties with the protective papers or tissues it has been found that due to the generation of static electricity, the insertion and removal c'f such protective papers is very diflicult for the oper or installer and substantially slows down the pacldng and unpacking of the tile which further increases packing packaging costs, as well as installation costs.

A general object of my present invention is to substantially reduce the possibility of tile face scoring or defacing by relative movements between engaged faces of adjacent tiles in a stack or package thereof without requiring the use of protective inserts, such as inserts of paper or tissue, between the adjacent faces of tiles in a stack or package thereof.

A further object is to provide `a design and construc* tion of plastic tile by which relative movements of the tiles in a stack thereof made up of pairs of back-to-back tiles will be confined primarily to relative movements which results from any relative movements between the tiles when they are out of substantial parallelism and angularly positioned relative to each other.

Another Objectis to provide a plastic tile` having at the rear or back side thereof a system and arrangement of leveling and positioning ribs by which an adjacent tile,

, when placed thereon in back-to-back relation therewith will tend to maintain a position substantially parallel therewith and thus eliminate the tendency of one tile to tilt or cant relative to the other with resulting increase in tile face damage, while permitting relative movements between the back-to-back tiles with a minimum of frictional resistance.

A further object is to provide a design and construction of such a system of positioning ribs which will be inexpensive to mold onto a plastic tile as integral parts thereof and which will not require expensive mold work.

A further object is to provide such a system of leveling and positioning rib members having the outer edges thereof forming suitable slideways which will pemit limited minimum friction movement of an adjacent tile thereover while maintaining the tiles in substantial parallelism. Y

And another general object is to eliminate or substantially reduce tile face damage during packing of the tiles and in'packages thereof by a simple and inexpensive construction of the tiles themselves so as to eliminate added handling operations and the use of additional packing materials in the packing and packaging thereof with the resulting substantial reduction in the high costs of the present packing and packaging methods.

Referring to the accompanying drawings in which similar reference characters refer to corresponding parts throughout the several figures thereof:

Fig. 1 is a view in rear elevation of the back or rear side of a plastic wall tile having a rearwardly extending edge ange therearound incorporating the system of positioning and leveling ribs of my invention..

Fig. 2 is a detail transverse sectional view through the tile of Fig. 1, taken as on the line 2 2 thereof, the thickness of the tile body, edge flange and rib being greatly exaggerated.

Fig. 3 is a transverse section also greatly exaggerated as to tile flange and rib thicknesses, taken through Vthe tile of Fig. l as von the line 3 3 thereof.

Fig. 4 is a perspective view of a stack of tiles of the design and construction of Fig. l with the tiles being arranged in pairs with the tiles of each pair in back-toback relation.

Fig. 5 is a transverse sectional view taken through adjacent pairs of the stack of tiles of Fig. 4, as on the line 5 5 of Fig. 4, the tile body, edge ilange and positioning ribs being greatly exaggerated in thickness.

Fig. 5a is a transverse sectional view similar to Fig. 5, but taken as on the line Srl-5a of Fig. 4 to show the side positioning ribs.

Fig. 5b is a View similar to Fig. 5a but showing one tile moved relative to the other with the tiles maintained parallel. Y f

Fig. 6 is a View in rear elevation of another form of plastic wall tile provided with the system and larrangement of leveling and positioning ribs of the` invention.V

Fig. 7 is a detail transverse sectional view throughthe tile of Fig. 'taken as on the line 7 7 thereof, the thick- Fig. 8 is a detail transverse sectional view through the tile of Fig. 6 taken as on the line 8 8 thereof, with the thickness ofthe tile body, flange and'sealing ribs being shown greatly exaggerated.

A plastic wall tile of a type now being widely manuf factured and installed, is disclosed in Fig. 1 of the drawings, as incorporating therein the system and arrangement of leveling and positioning rib members of my present invention.Y This plastic wall tile T of Fig. l is square in plan, having Vdimensions of approximately 4% x 41/4 across the rear or back side of the tile, with a thin, plate-like body 10 having completely therearound the continuous and unbroken rearwardly extending edge flange 11 extending from the back or rear side 12 of the tile body 10. These plastic tile of the general` form exemplied by the tile T ofY Fig. l are usually injection molded from suitable thermoplastic materials or compositions, such, for example, as a polystyrene composition, with the tile body 10 in this instance having a thickness of the order of approximately .062. The rearwardly turned edge ange may be taken to have a thickness*V of approximately 0.048", with the width of the rear edge surface thereof being of the order of approximately Y 0.032. The maximum over-all thickness or depth yof the tile T of Fig. 1 from the front or face forming side 14 thereof to the edge surface 11a iof the edge'ilange 11 may be taken to be approximately 0.10 while the depth of the edge flange 11 from the bevel surface 11b which it forms with the face side 14 is approximately 0.107". The standard tile of the type of tile T of Fig. l comprises solely the tile body 10 andthe rearwardly extending edge iiange 11.V It will therefore be readily appreciated that when a pair of tile of such Va construc-v tion are placed back-to-back with the vedge anges 11 thereof abutting and engaged, one tile, due to the very thin or narrow Width rear surfaces 11a of the edge flange 11 thereof will readily slide or slip laterally relative to the other tile so that one side or corner portion of one tile will slip inwardly into canted or tilted position relative to the other. When in such a tilted position, the tile will resist efforts to push it backinto proper position in substantial parallelism with the other tile because the edge flange of the tilted tile will engage against the inner side of the adjacent edge flange of the other tile. Now, when pairs of tile of this standard, widely-usedtype are packaged by stacking them in pairs in the manner hereinbefore described, it will be apparent that there will be many of the tiles of the stack which will slip from parallelism with the adjacent tiles and thus cant or tilt into relative positions in which handling and movement of a package containing such stack will result in rubbing, abrasive action between the engaged faces of the canted or tilted tiles and the adjacent tiles. This results in marring or defacing the decorative faces of the tiles and causes rejection of such defaced tiles by the purchaser, with the consequent loss to the manufacturer and/ or the seller.

By my present invention I have effectively overcome the problem of tile defacement and damage in the pack-V ing of the tiles in stacks and in the packaging of such stacks of tiles by providing a system and arrangement of leveling and positioning components lon the rear or back sides of the tiles in the form of relatively small and narrow rib members which may be molded integrally with each tile at no substantial increase in the cost of the tile over the standard or conventional forms thereof. With the plain type of flanged plastic wall tile of the form of Figs. l through 4, such system of rib members, referring now to Fig. l, may comprise the diagonally positioned corner ribs20 and the side ribs 30 positioned along each side length of the rearwardly extending edge flange 11. In this particular example, because of the square form and dimensions of the 'tile T, I have provided each side portion of the edge flange 11 with two (2) of such rib members 3G spaced substantially equal distances apart along such flange portion. In this system of leveling and positioning rib members and 30, the rib members are molded integrally with the rear side 12 of the tile body 1G and with the inner sides of the flange 11 around the edge of the tile body, as will be clear by reference to Fig. l.

Each corner rib member 20 in the example hereof extends inwardly at an angle of approximately 45 to flange 11 from the corner edge 15 formed by the joindure of the adjacent flange portions 11 a distance on and across the rear side 12 of the body 10. Each corner rib member 2* projects rearwardly from the rear surface of the rear side 12 of the tile body and from its outer end for a distance inwardly from flange corner 15 has a depth such that the upper edge surface 21 thereof lies in the plane of the rear edge surface 11a of the flange 11, as will be clear by reference to Fig. 2. From a point intermediate of its length the rib member 26 progressively decreases in depth to provide the inwardly inclined upper edge surface 22 which terminates at its inner end at and merges into the rear surface of the back or rear side 12 of the tile body 10. The upper edge surface 21 of a corner rib member 20 which lies in the plane of the rear edge 11a of flange 11 provides a slideway or guide surface adapted to be engaged by portions of the back or rear of an adjacent tile placed in back-to-back relation therewith, as will be more fully explained hereinafter.

The so-called side rib members 30 are generally similar in thickness or width to the corner rib members 2t) but are of less length. Each of such rib members 30 is molded integrally with the tile body and the flange 11 in position extending rearwardly from the tile body 1t? at the rear side 12 thereof for a distance inwardly from that portion of flange 11 with which it is integrally joined. Each side rib member 3d has a portion thereof extending inwardly from the flange 11 to a location intermediate the length of the rib of a depth such that the rear edge surface 31 thereof lies substantially in the plane `of the rear edge surface 11a of the ange with the rib member then progressively decreasing in depth from such intermediate location to its inner end to provide the inwardly inclined rear edge surface 32. The inner end of the inclined surface 32 merges into and joins with the rear surface of the rear side 12 of the body 10. The rear edge surfaces 31 of the spaced side ribs 30 provide slideways or guide surfaces for engagement by portions of the back of a tile when placed in back-to-back relation therewith. These side rib members 3@ are in the instant example positioned substantially normal to the sections or portions of the tile edge flange 11 from which they extend, as will be clear by reference to Fig. l.

I have shown in Fig. 4 of the drawings a stack or partial stack of tile pairs P each made up of tiles T pla-ced in back-to-back relation with the faces 14 of the adjacent tiles of adjacent pairs being in abutting engagement over substantially the entire face areas thereof. From a consideration of Fig. 4 it will be apparent that such a stack of tiles made up of pairs of the conventional flanged tiles of commerce will, as to the tiles of each pair, be merely supported in their back-to-back relation when in the desired parallelism only by the edge anges 11 thereof when the narrow rear edge surfaces 11a of such edge flanges are abutting and seating on each other. The slightest movement of or force applied to one of the tiles of a pair of tiles will dislodge and displace it from position supported in parallelism with the other by the abutting tile edge ianges 11 and the tiles will then take the undesired positions canted or tilted from parallel relation, as hereinbefore referred to and described. However, with the tiles T embodying the system of leveling and positioning rib members 2e and 36 of my invention, such displacement of the tiles from the desired parallel relation therebetween is prevented by the series of inwardly extending slideways 21 and 31 of the rib members 20 and 30 spaced apart around the tiles of a pair of back-to-back tiles. This is so because, with such rib members spaced apart around the tiles and providing the inwardly extending guide surfaces or slideways, the rib members will be aligned and engaged upon each other when the tiles of the pair are truly aligned one upon the other. And if one tile is displaced from such true position of alignment with the other, it will be maintained in its parallel relation with the other tile due to the inwardly extending slideways 21 and 31 of the rib members 20 and 30 positioned as these slideways are in the planes of the rear edges 11a of the flanges of their respective tiles. Thus the tiles T of each of the pairs of back-to-back tiles in a stack of such pairs, such as in the tile stack shown in Fig. 4, may have limited relative movements therebetween in any direction in the planes thereof, but such relative movement or" a tile will always be in a plane substantially parallel with the tiles adjacent thereto. in stacking the tiles for packaging the operator may handle and stack the tiles rapidly with assurance that they will maintain parallel positions, and interlocking between the back-to-back tiles will be prevented as the tiles will not in the normal handling thereof cant or tilt relative to each other.

In addition to the maintenance of substantial parallelism between the tiles, another important feature of my invention which contributes to the solution of the problem of defacement of packaged tiles caused by vibration in transit and in handling is the substantial elimination of relative movements between the engaged faces of tiles of adjacent pairs of back-to-back tiles in a package thereof, by the transfer and concentration of relative movements to movements between the backs of the tiles in the pairs of back-to-back tiles. This result is obtained due to the i' rge frictional resistance aided by static locking between engaged faces of adjacent pairs of tiles compared to the relatively small frictional resistance between the lsmaller engaged surface areas at the backs of each pair of tiles. Hence, with the elimination of interlocking `and tilting between the tiles of each pair of back-to-back tiles and the maintaining of the tiles parallel even when relatively moved (see Fig. 5b) the required relative movements resulting from vibration in the transportation and handling of the packaged tiles is met and satisfied by movements between the tiles of' the pairs of back-to-back tiles with rubbing andface marring by relative movementsbetween the engaged faces of tiles of adjacent pairs reduced to a minimum.

ln Figs. 6, 7 and S I have disclosed a self-sealing form of plastic wall tile of my invention which is disclosed and claimed in an application for patent tiled by me and now pending in the United States Patent Oce. I have shown this form of self-sealing wall tile herein Ias incorporating and embodying the system of leveling and positioning ribs of my present invention as hereinbefore described and discussed in the appli-cation thereof to the well-known and widely used plain anged Wall tile of the commercial art. Referring to Fig. 6 in particular, Ia self-sealing plastic wall tile ST is disclosed as of the dimensions and body and flange thicknesses of the order hereinbefore set forth in connection with the plain wall tile of Fig. 1. This wall tile ST incorporates the relatively thin plastic material body it! and rearwardly extending edge ange 11 of the tile as shown in Figs. l through 5. However, tile ST is pravided on the rear or back side thereof with a plurality1 et' spaced parallel sealing ribs 4t? extending along and parallel with the side portions 11, respectively, making up the frange 11. The outermost sealing rib 4t) is spaced inwardly a distance from the adjacent side por. tion of the edge flange 1l `and the sealing ribs 40 extend completely across that side of the tile on which they are located and intersect and cross at their ends with the adjacent ends of the sealing ribs 40 along the adjacent rear surface of the tile.

sides of the back of the tile. The intersection and crossing-over of the ends of each side set of sealing ribs 40 thus forms in each corner of the rear side of the tile the relatively square, closed side recesses 41 between the crossed end lengths of the sealing ribs, as will be clear by reference to Fig. 6. In the specific form of tile ST of this example the upper edge surfaces of the ribs 40 lie in planes spaced a distance inwardly from `a plane passing through the rear edge surfaces 11a of the ilange 11.

A system of leveling `and positioning ribs in an arrangement similar to that providedY on the tile T of Fig. l is incorporated on the rear side of the self-sealing form of tile STand comprises the corner rib members 50 and the side rib members 60. The corner rib members 50 are substantially identical with the rib members 20 of a tile T of Fig. l, and such rib members extend from each corner of the ilange 11 inwardly over and rearwardly from the rear side of tile ST at an angle of substantially 45 to the adjacent side portions of the ilange 11. Each corner rib member Sil provides the rear edge surface 51 extending from the adjacent corner 15 inwardly a distance from the corner 15 in the plane of the rear edges 11a of the flange 1l. The rear or inner length of each corner rib member 5t) has the progressively inwardly inclined rear edge surface 52 similar to the rear edge sur-face 22 of a corner rib member of the tile T.

The side rib members 60 of the tile ST are generally similar in location on the rear side of the tile to the side rib members of tile T but extend across and intersect the sealing ribs in the manner shown in Fig. 7. Each side rib member has the rear edge 61 thereof located in the plane of the rear edge 11a of the adjacent portion of llange 11 with which the side rib member is integrally joined. From the rear or inner end of the rear edge surface 61 the rear surface 62 thereof is progressively inclined inwardly to and joins at its inner end with the The rear edge surfaces 61 and 62 of each side rib member 60 thus provide slideways or ramps by which the ribs and flange at the rear side of an adjacent tile ST when a pair of tiles are placed in backto-back relation will be guided and prevented from interlocking with the maintenance of parallelism between the tiles being thereby aided in'conjunction with the functioning of the corner rib members 50.

It will be clear from the detailed explanation of the functioning of and the results from the system of leveling and positioning ribs of the invention as incorporated in the tile T of Fig. l, that when such system is incorporated in the tile of the form of tile ST of Fig. 6, the same results in the maintenance of parallel relationship between tiles of a pair and tiles adjacent to the pair will be obtained so that elimination or substantial reduction in damage to engaged tile faces due to relative movements therebetween in a stack of such tiles will result.

While in the selected examples hereof I have shown plastic tiles of square plan shape, such showing is not by way of limitation as the system of leveling and positioning rib members in accordance with the invention may be applied to tiles of any tile shape, including the rectangular, the circular, and various other curved edge or perimeter shape of tile. Similarly, in the examples selected I have shown two (2) side rib members from each side portion of the tile edge ange, but such number is in no sense critical in either the tiles of the illustrated examples or in any other shape or size of tile. The number of side rib members will be primarily determined by the dimensions of the tile as well as by its particular shape. In certain instances I contemplate and intend that only the diagonally disposed corner positioning rib members need be used and therefore my invention in all respects is not essentially limited to the inclusion of the side rib members. Similarly, if desired in certain instances, the corner rib members may be eliminated and the side rib members only used in relative locations on the tile to include the function of the corner rib members.

In the illustrated examples the side rib members are shown as of less length than the corner rib members butsuch length relationship is not basically essential to a proper functioning and to eicient results from tiles, including the positioning rib systems'of the invention.

It will also be evident that various other modifications, variations, embodiments, constructions, arrangements and combinations may be resorted to without departing from the' broad spirit and scope of my invention and, hence, I do not desire or intend to limit the invention in all respects to the exact andV specific disclosures of the selected exampleshereof, except as may be required by specific and intended limitation thereto appearing in any of the claims hereto appended.

What I claim is:

l. An all-plastic tile comprising, in combination, a thin, light-weight, plastic material tile body of plate form providing a front side having a substantially planar front face area thereover, an opposite generally parallel rear side having a substantially planar rear surface area thereover, and outer side edges therearound; said tile body having rearwardly extending side edge llanges along and integral with said outer side edges of said tile body, respectively, with the rear edges of said side edge flanges located in a substantially` common plane; said rearwardly extending side edge flanges being integrally joined at the corners, respectively, of said tile body forming a continuous side edge flange therearound surrounding said rear surface of said rear side of said tile body; a plurality of side positioning rib members integrally joined at their outer ends with and extending vshort distances inwardly from` and disposed transversely relative to each of said side edge anges at spaced intervals therealong; corner positioning rib members on the rear side of said tile body at the i corners thereof with the outerends ofisaid corner positioning rib members integrally joined with said side edge anges; said corner positioning rib members extending transversely inwardly short distances over the rear side of said tile body integrally therewith; and said side positioning rib members and'said corner positioning rib members having the rear edges thereof from their outer ends at said side edge flanges to locations intermedate their lengths located'substantially in the common plane of the rear edges of said edge llan'ges; and said side positioning rib members and Vsaid corner positioning rib members having their rear edges from said intermediate locations thereon progressively inclined inwardly to and merging at their inner ends into said rear surface of the rear side of said tile body. i

2. A plastic wall tile comprising, in combination, a thin plastic material tile body of plate form providing a front side having a substantially planar front face area thereover, an opposite generally parallel rear side having a rear surface area thereover, and outer side edges therearound; said tile body having rearwardly extending edge flanges along and integral with said outer side edges thereof with the rear edges of said flanges located in a substantially common plane; said rearwardly extended edge flanges being joined at the corners, respectively, Vof said tile body forming a continuous edge flange therearound surrounding said rear surface of said rear side of said tile body; sealing ribs on the rear side of said tile body around the inner side of and parallel with said edge flanges positioned in close proximity thereto spaced inwardly a small distance therefrom forming narrow channels therebetween; said sealing ribs having the rear edges thereof located in planes spaced inwardly in a direction toward said rear surface of said tile body from the Y'cornmon plane of said rear edges of said edge iianges; positioning rib members integrally joined at their outer ends with and extending inwardly from each of said edge flanges at spaced intervals therealong; said positioning rib members extending transversely inwardly across and integral with said sealing rib members over and integral with said rear surface of said tile body; each of said positioning rib members having the rear edge thereof located substantially in the common plane of the rear edges of said edge flange from the outer end of said positioning rib member at said edge ange to a location intermediate the length of said positioning rib member at the inner side of said sealing ribs; and the rear edge of each of said positioning rib members from said intermediate location thereon being progressively inclined inwardly to and merging at the inner end thereof into the rear surface of the rear side of said tile body.

3. An all-plastic wall tile comprising, in combination, a thin, light-weight, plastic material tile body of plate form providing a front side having a substantially planar front face area thereover, an opposite generally parallel rear side having a rear surface area thereover, and outer side edges therearound; said tile body having rearwardly extending edge iianges along and integral with said outer side edges thereof, respectively, with the rear edges of said edge flanges located in a substantially common plane; said rearwardly extending edge anges being joined at the corners, respectively, of said tile body forming a continuous rearwardly extending edge ange therearound surrounding said rear surface of said rear side of said tile body; sealing ribs on the rear side of said tile body around the inner side of and parallel with said edge flanges positioned in close proximity thereto spaced inwardly a small distance therefrom forming narrow channels therebetween; said sealing ribs having the rear edges thereof located in planes spaced inwardly in a direction toward said rear surface of said tile body from the common plane of said rear edges of said edge anges; side positioning rib members integrally joined at their outer ends with and extending inwardly from each of said edge llanges at spaced intervals therealong; said side positioning rib members extending transversely inwardly across and integral with said sealing rib members over and integral with said rear surface of said tile body; a corner positioning rib member located on the rear side of said tile body at each corner of said continuous edge flange with its outer end integrally joined with said edge ange at such corner;

each of said corner positioning rib members extending diagonally inwardly over said rear side of said tile body integral therewith and across and integral with said sealing rib members; each of said side positioning rib members having the rear edge thereof located substantially in the common plane of the rear edges of said edge flange from the outer end of said side positioning rib member at said edge ange to a location at the inner side of said sealing ribs intermediate the length of said side positioning rib member; the rear edge of each of said side positioning rib members from said intermediate location thereon being progressively inclined inwardly to and merging at the inner end thereof into the rear surface of the rear side of said tile body; each of said diagonally extending corner positioning rib members having the rear edge thereof in substantially the common plane of the rear edges of said edge flanges from said corner of said edge iiange to a location intermediate the length of said corner positioning rib member spaced inwardly of said sealing ribs; and the rear edge of each of said corner positioning rib members from said intermediate location being progressively inclined inwardly to and merging at its inner end into the rear surface of said rear side of said tile body.

References Cited in the le of this patent UNITED STATES PATENTS 723,979 Blackmore Mar. 31, 1903 1,690,259 Strauss Nov. 6, 1928 1,702,912 McCoy Feb. 19, 1929 2,156,149 Feichter Apr. 25, 1939 2,425,619 Juergens Aug. 12, 1947 2,645,329 Blair July 14, 1953 2,666,373 Mattson Jan. 19, 1954 FOREIGN PATENTS 3,727 Great Britain 1909 446,435 France 1912 434,297 Great Britain 1935 438,599 Great Britain 1935 615,609 Great Britain 1949

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